On Wed, Jun 10, 2015 at 03:43:03PM +0200, Thibaut Collet wrote:
> In case of live migration with legacy guest (without
> VIRTIO_NET_F_GUEST_ANNOUNCE)
> a message is added between QEMU and the vhost client/backend.
> This message provides the RARP content, prepared by QEMU, to the vhost
> client/backend.
> The vhost client/backend is responsible to send the RARP.
>
> Signed-off-by: Thibaut Collet <thibaut.col...@6wind.com>
> ---
> docs/specs/vhost-user.txt | 16 ++++++++++++++++
> hw/net/vhost_net.c | 8 ++++++++
> hw/virtio/vhost-user.c | 11 ++++++++++-
> linux-headers/linux/vhost.h | 9 +++++++++
> 4 files changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 2c8e934..ef5d475 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -97,6 +97,7 @@ typedef struct VhostUserMsg {
> uint64_t u64;
> struct vhost_vring_state state;
> struct vhost_vring_addr addr;
> + struct vhost_inject_rarp rarp;
> VhostUserMemory memory;
> };
> } QEMU_PACKED VhostUserMsg;
> @@ -132,6 +133,12 @@ Multi queue support
> The protocol supports multiple queues by setting all index fields in the sent
> messages to a properly calculated value.
>
> +Live migration support
> +----------------------
> +The protocol supports live migration. GARP from the migrated guest is done
> +through the VIRTIO_NET_F_GUEST_ANNOUNCE mechanism for guest that supports it
> or
> +through RARP.
> +
> Message types
> -------------
>
> @@ -269,3 +276,12 @@ Message types
> Bits (0-7) of the payload contain the vring index. Bit 8 is the
> invalid FD flag. This flag is set when there is no file descriptor
> in the ancillary data.
> +
> + * VHOST_USER_NET_INJECT_RARP
> +
> + Id: 15
> + Master payload: rarp content
> +
> + Provide the RARP message to send to the guest after a live migration.
> This
> + message is sent only for guest that does not support
> + VIRTIO_NET_F_GUEST_ANNOUNCE.
I don't see why this is needed.
Can't backend simply send rarp itself?
Why do we need to involve QEMU?
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 4a42325..f66d48d 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -369,10 +369,18 @@ void vhost_net_stop(VirtIODevice *dev, NetClientState
> *ncs,
>
> void vhost_net_inject_rarp(struct vhost_net *net, const uint8_t *buf, size_t
> size)
> {
> + struct vhost_inject_rarp inject_rarp;
> + memcpy(&inject_rarp.rarp, buf, size);
> +
> if ((net->dev.acked_features & (1 << VIRTIO_NET_F_GUEST_ANNOUNCE)) == 0)
> {
> + const VhostOps *vhost_ops = net->dev.vhost_ops;
> + int r;
> +
> fprintf(stderr,
> "Warning: Guest with no VIRTIO_NET_F_GUEST_ANNOUNCE support.
> RARP must be sent by vhost-user backend\n");
> fflush(stderr);
> + r = vhost_ops->vhost_call(&net->dev, VHOST_NET_INJECT_RARP,
> &inject_rarp);
> + assert(r >= 0);
> }
> }
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index d6f2163..2e752ab 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -41,6 +41,7 @@ typedef enum VhostUserRequest {
> VHOST_USER_SET_VRING_KICK = 12,
> VHOST_USER_SET_VRING_CALL = 13,
> VHOST_USER_SET_VRING_ERR = 14,
> + VHOST_USER_NET_INJECT_RARP = 15,
> VHOST_USER_MAX
> } VhostUserRequest;
>
> @@ -70,6 +71,7 @@ typedef struct VhostUserMsg {
> uint64_t u64;
> struct vhost_vring_state state;
> struct vhost_vring_addr addr;
> + struct vhost_inject_rarp rarp;
> VhostUserMemory memory;
> };
> } QEMU_PACKED VhostUserMsg;
> @@ -104,7 +106,8 @@ static unsigned long int
> ioctl_to_vhost_user_request[VHOST_USER_MAX] = {
> VHOST_GET_VRING_BASE, /* VHOST_USER_GET_VRING_BASE */
> VHOST_SET_VRING_KICK, /* VHOST_USER_SET_VRING_KICK */
> VHOST_SET_VRING_CALL, /* VHOST_USER_SET_VRING_CALL */
> - VHOST_SET_VRING_ERR /* VHOST_USER_SET_VRING_ERR */
> + VHOST_SET_VRING_ERR, /* VHOST_USER_SET_VRING_ERR */
> + VHOST_NET_INJECT_RARP /* VHOST_USER_NET_INJECT_RARP */
> };
>
> static VhostUserRequest vhost_user_request_translate(unsigned long int
> request)
> @@ -287,6 +290,12 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
> msg.u64 |= VHOST_USER_VRING_NOFD_MASK;
> }
> break;
> +
> + case VHOST_NET_INJECT_RARP:
> + memcpy(&msg.rarp, arg, sizeof(struct vhost_inject_rarp));
> + msg.size = sizeof(struct vhost_inject_rarp);
> + break;
> +
> default:
> error_report("vhost-user trying to send unhandled ioctl");
> return -1;
> diff --git a/linux-headers/linux/vhost.h b/linux-headers/linux/vhost.h
> index c656f61..1920134 100644
> --- a/linux-headers/linux/vhost.h
> +++ b/linux-headers/linux/vhost.h
> @@ -63,6 +63,10 @@ struct vhost_memory {
> struct vhost_memory_region regions[0];
> };
>
> +struct vhost_inject_rarp {
> + __u8 rarp[60];
> +};
> +
> /* ioctls */
>
> #define VHOST_VIRTIO 0xAF
> @@ -121,6 +125,11 @@ struct vhost_memory {
> * device. This can be used to stop the ring (e.g. for migration). */
> #define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct
> vhost_vring_file)
>
> +/* Inject a RARP in case of live migration for guest that does not support
> + * VIRTIO_NET_F_GUEST_ANNOUNCE */
> +#define VHOST_NET_INJECT_RARP _IOW(VHOST_VIRTIO, 0x31, struct
> vhost_inject_rarp)
> +
> +
> /* Feature bits */
> /* Log all write descriptors. Can be changed while device is active. */
> #define VHOST_F_LOG_ALL 26
> --
> 1.7.10.4
